CVE-2024-42739
📋 TL;DR
This CVE describes an authenticated OS command injection vulnerability in TOTOLINK X5000r routers. Attackers with valid credentials can execute arbitrary commands on the device by sending malicious packets to the vulnerable CGI endpoint. This affects users running the specific vulnerable firmware version.
💻 Affected Systems
- TOTOLINK X5000r
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing installation of persistent backdoors, credential theft, lateral movement to connected networks, and use as a botnet node.
Likely Case
Unauthorized command execution leading to network reconnaissance, data exfiltration, or denial of service against the router.
If Mitigated
Limited impact if strong authentication controls, network segmentation, and proper monitoring are in place.
🎯 Exploit Status
Exploit details and proof-of-concept are publicly available in the GitHub reference. Attack requires valid credentials.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: Yes
Instructions:
1. Check TOTOLINK website for firmware updates
2. Download latest firmware for X5000r
3. Access router admin interface
4. Navigate to firmware upgrade section
5. Upload and apply new firmware
6. Reboot router after update
🔧 Temporary Workarounds
Disable remote administration
allPrevent external access to router administration interface
Restrict admin access
allLimit administrative access to specific IP addresses only
🧯 If You Can't Patch
- Isolate vulnerable routers in separate network segments
- Implement strict firewall rules to limit router management access
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface under System Status or Firmware Upgrade sectionCheck Version:
Login to router web interface and navigate to System Status pageVerify Fix Applied:
Verify firmware version has been updated to a version newer than v9.1.0cu.2350_b20230313📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /cgi-bin/cstecgi.cgi with command injection patterns
- Multiple failed login attempts followed by successful login and command execution
Network Indicators:
- Unusual outbound connections from router to external IPs
- Unexpected network traffic patterns from router
SIEM Query:
source="router_logs" AND (uri="/cgi-bin/cstecgi.cgi" AND (method="POST" AND (body="setAccessDeviceCfg" AND (body="|" OR body="$" OR body="`" OR body=";"))))